In many electronic systems, such as wireless devices, mobile devices and so forth many or all components of the system are interconnected by a two-wire bus (clock and data) which follows the inter-integrated circuit (I2C) standard. Usually a central microcontroller (i.e., a host) will implement an “I2C master” function, which allows it to initiate data transfers to and from the other components in the system. The other components will implement a slave controller function, which generally includes a set of registers that can be written or read by the host to control the functions of the component. Each slave is identified by a unique address sent by the master at the beginning of each transaction to identify the intended slave.
In a complex system, the shared I2C bus may be very active, since the host may be frequently communicating with many of the components in the system. This activity is a source of electrical noise that couples into all of the components connected to the bus. The noise can be especially problematic for analog circuitry such as present wireless systems that may include a radio frequency (RF) tuner, since such analog circuitry is very sensitive to noise. Specifically, the tuner includes circuitry to amplify very low voltage signals from a receiving antenna, high-frequency oscillators, analog mixers, and circuitry to perform analog-to-digital and digital-to-analog conversion. A need thus exists to isolate such analog circuitry in order to reduce the amount of noise encountered by, e.g., an RF tuner.